Production of cumylphenol from alpha-methylstyrene dimer



United States Patent William D. Griflin, Convent Station, and George G.Joris,

Madison, NJ., assignors to Allied Chemical Corporation, New York, N.Y.,a corporation of New York No Drawing. Application January 23, 1957Serial No. 635,591

4 Claims. (Cl. 260619) This invention relates to the production ofpara-we'- dimethyl benzyl phenol, more briefly called cumylphenolhereinafter in this specification.

- Certain phenol still residues, particularly those which are obtainedin the process of making phenol from cumene contain substantial amountsof a-methylstyrene dimer 2,5-diphenyl hexene-2 in addition to phenol andby-products such as cumylphenol and acetophenone. This dimer has in thepast been discarded as a relatively useless by-product. It has now beenfound, however, that the otherwise undesirable dimer 2,5-diphenylhexene-Z can be reacted with excess phenol to form additionalcumylphenol prior to separation of the reactants from the residue andthus considerably enhance the yield of highly desirable cumylphenolobtainable from the residue. The process is a simple one-step processwhich pro ceeds according to the following equation in which 2,5-diphenyl hexene-Z, an open-chain a-methylstyrene dimer,

2 catalyst such as concentrated sulfuric acid and under temperatureconditions which lie within the range of about 1l0-140' C. The reactiongoes to completion-in labour or-less and yields of.80- have beenobtained based on phenol consumed.

Not only is the process particularly well-adapted for use in enhancingthe yield of cumylphenol obtainable from phenol still bottom residuesbut it can alsobe used effectively to produce cumylphenol from thedimers ot a-methyl-styrene after they have been isolated or when theyare in the presence of other ingredients which will not interfere withthe reaction between phenol and the dimer in the presence of a catalystsuch as sulfuric acid;

The specific catalyst which has been found most effective isconcentrated sulfuric acid. This catalyst can be used effectively inconcentrations within the range of O.5l.5% of the total. The preferredconcentration, however, is about l%. For optimum results the reaction ofthe phenol with the dimer requires a mol ratio of phenol to dimer of atleast 2:1. Higher ratios such as 4:1 and 8:1 do not-adversely afiect theyield of cumylphenol.

Best yields have been observed when operating at temperatures of about110 C. 1

Example I.To a phenol still bottom which contain 22.1 parts ofcumylphenol, 37 parts dimer, 2,5-diphenyl hexane-2, 10 partsacetophenone, 0 part phenol and 31 parts of unidentified organic matterwere added 59 parts by weight of phenol, about twice the theoreticalamount of phenol required to react with the dimer present. This broughtthe molar ratio of phenol to dimer to 4:1. This material was thenreacted in the presence of controlled amounts of concentrated commercialsulfuric acid (96% The results are summarized in Table No. 1.

TABLE NO. 1

Formation of cumylphenol [Starting materials: wt. phenol still bottomsplus 59 wt. phenol. Molar ratio phenol to dimer: 4:1.)

wt Percent Composition by IR Analysis Percent yield 01 Test No. Temp.,Percent, Time, cumy phenol C. H2304 HIS.

Cumyl- Aceto- Unphenol Phenol Dimer pheknown Phenol Dimer none Stillbottom 0 11. 2 37. 8 20 5. 8 25. 2 1 140 1. 5 1 32. 2 26.9 2. 5 5. 632.8 85 67 4 29. l 25. 5 1.4 4. 9 39. 2 65 54 2 i 0. 5 30 28. 2 trace 5.7 36. 1 87 52 1. 5 31:9 26. 2 trace 5. 4 36. 5 79 58 2. 5 28. 5 24 trace5. 6 41. 9 48 56 3 141 0. 5 0. 33 13. 5 38. 6 9. 5 6 32. 4 12 2 15. 238. 2 5 6. 2 35. 4 15 4 110 0. 5 0. 33 13. 7 38. 2 15 5.8 27. 3 28 2. 513. 7 37 10 6. 2 33.1 14 5 1. 0 0. 5 27. 1 27. 1 3 5. 5 37. 3 63 50reacts with two mols of phenol to form two mols of cumylphenol.

The reaction is suitably carried out in the presence of a of the purereactants (plus catalyst) are summarized in Table No. 2.

TABLE NO. 2

Formation of cumylplrenol Catalyst for all runs: 1% sulfuric acidProduct (IR Anal) Percent Y! m e Based on Bun No. Initial Molar Reno.Dimer Ratio, Time, Cumyl Un 0HI Temp, Hr. H OH known Percent PercentDimer '0.

e011 Dimer l 61.5 38.5 4:1 140 K 44. 5 36.2 19. 3 52 56 46. 4 36.9 16. 753 i. 61. 5 38. 5 4:1 110 K 45. 5 40. 8 13. 7 59 3 45.8 38. 1 16.1 55 141. 5 37.5 21 54 1.. 70. 5 29. 5 6:1 110 K 80 30 10 51 1 58 29 13 55 476. 1 23. 9 8:1 110 M 58.1 23 8. 9 54 l 68 24 8 56 These runs withsulfuric acid as catalyst were maintained uniformly at 1% H 80concentration. It is evident from the data obtained that the requiredreaction time in all cases was very short, less than minutes, since nodimer was detected in the product. Furthermore, some data indicate thatprolonged reaction times lead to decreased yields of cumylphenol.Comparable tests which were run at 140 and 110' C. respectively resultedin somewhat better yields at the low temperature. The data tend toindicate that varying the initial molar ratio of phenol to dimer in therange of 4:1 to 8:1 has little efiect on the yields. Example 3.-A stillbottom (analyzing 0% phenol, 22.1% cumylphenol, 37% dimer, 10%acetophenone, 31% unknown) was reacted with excess phenol (molar ratiophenol to dimer of 4:1) at 140 0., catalyzed by 1% concentratedcommercial sulfuric acid (based on total mixture); reaction time was 0.5hour. The product was neutralized and distilled, from which data thecomposition was calculated to be 1.6% water, 25.3% phenol, 5.9%acetophenone, 0.6% dimer, 32.7% cumylphenol, and 33.9% unknown.Calculations from these data show the yields of cumylphenol to be 67.8%from the phenol and 42.6% from dimer. Material losses throughout thisrun were extremely small.

Example 4.A still bottom was maintained at 128 C. for 0.5 hour in thepresence of 1% sulfuric acid. The initial analysis was 31.7% phenol,13.1% cumyphenol, 13.6% dimer, 12.4% acetophenone and 29.1% unknown, fora phenol to dimer molar ratio of 5.9: I; no phenol was added in thiscase. Analysis of the reaction product indicated 26.4% phenol, 21.3%cumylphenol, 13% acetophenone, 0% dimer, 39.3% unknown. Yields ofcumylphenol calculated from these figures were 67.3 percent based onphenol and 33.5 percent based on dimer.

It is a relatively simple matter to recover the cumylphenol and theother components from the reaction products after the dimer has beenconverted in accordance with the process outlined above. It is suitableto first neutralize the reaction products and then subject them to adistillation in which case the first overhead product which is recoveredup to 101 C. at 33 mm. of pressure is phenol. The second overheadrecovered up to 130 C. at 14 mm. pressure is acetophenone and the thirdfraction recovered up to -l97 C. at 4 mm. pressure is the cumylphenol.

While the above description submitted herewith discloses a preferred andpractical embodiment of the production of cumylphenol froma-methylstyrene dimer in accordance with the invention, it will beunderstood that the specific details described are by way ofillustration and are not to be construed as limiting the scope of theinvention. i

We claim:

1. The method of preparing para-a-wdimethyl benzyl phenol whichcomprises condensing phenol with 2,5-diphenyl hexene-Z in the presenceof concentrated sulfuric acid as catalyst.

2. The method of preparing para-a-a-dimethyl benzyl phenol whichcomprises treating phenol still bottoms containing 2,5-diphenyl hexane-2as one of its components with an excess of phenol in the presence ofconcentrated sulfuric acid as catalyst.

3. The method of preparing para-a-a-dimethyl benzyl phenol whichcomprises treating phenol still bottoms containing 2,5-diphenyl hexene-Zas one of its components with an excess of phenol in the presence ofconcentrated sulfuric acid as catalyst, at a temperature lying withinthe range of about l10140 C.

4. The method of preparing para-a-a-dimethyl beuzyl phenol whichcomprises treating phenol still bottoms con taining 2,5-diphenylhexene-Z as one of its ingredients with phenol in the presence ofconcentrated sulfuric acid as a catalyst at a temperature lying withinthe range of 1l0l40 C.

References Cited in the tile of this patent UNITED STATES PATENTS2,091,565 Perkins et al. Aug. 31, 1937 2,388,583 Ward Nov. 6, 19452,720,549 Armstrong et al Oct. ll, 1955 2,757,209 Joris July 31, 1956OTHER REFERENCES Bergman ct al.: Chem. Abstracts, vol. 25 (1931), pp.4239-40.

Ellis: Chemistry of Petroleum Derivatives," page 612. pub. by ChemicalCatalog Co. (1934), New York, hLY.

1. THE METHOD OF PREPARING PARA-A-A-DIMETHYL BENZYL PHENOL WHICHCOMPRISES CONDENSING PHENOL WITH 2,5-DIPHENYL HEXENE-2 IN THE PRESENCEOF CONCENTRATED SULFURIC ACID AS CATALYST.